torsdag 8. juni 2017

S-curve shows transition to disruptive technology

The two previous blog posts show that the transition to wind and solar energy in the electricity production has started, both globally and in China, the largest emitter of greenhouse gases. It is now cheaper to build new electricity plants based on wind and solar than based on nuclear and fossil fuels. Wind and solar are therefore often regarded as disruptive technologies.

Generally, a disruptive technology will replace the older technology, and the transition will follow an S-curve.

Figure 1: The S-curve shows how the market share of a disruptive technology evolves. The curve flattens when the market share reaches its saturation level.

The curves showing the electricity production in the recent years by both wind and solar resemble the start of an S-curve. But there are topics for wind and solar that may cause the further evolution to differ from the S-curve. China, as the rest of the world, wants to phase out fossil fuels in its electricity production as fast as possible due to both global warming and local pollution. This may cause the transition to be even faster than the S-curve.

Wind and solar both have intermittency problems. We need electricity also when the wind does not blow and the sun does not shine. The intermittency problems become more and more serious as the shares of wind and solar increase. This may cause the transition to be slower than the S-curve.

There are some solutions to the intermittency problems, and new solutions will certainly be developed. Chris Goodall discusses these problems in his latest book The Switch. He writes that various solutions have to be applied, in part simultaneously. Many of the solutions are technical, but not all of them. A technical solution is to produce hydrogen and gas for later use when there is a  surplus of solar and wind electricity. A non-technical solution is to control the demand for electricity using varying prices so that demand better matches production.

Solar, wind, hydro and the other renewables have different properties. Their saturation levels measured in percent of the total market will therefore vary around the world. The S-curve in Figure 1 may represent the electricity production by solar and wind, and the saturation level may be the production needed to totally phase out the electricity produced by fossil fuels.

The rest of the blog post deals with mathematical details about S-curves.